Metrohm 855 Robotic Titrosampler - Manual (Page 58)

7.1 Measuring interface ￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭
50 ￭￭￭￭￭￭￭￭ 855 Robotic Titrosampler
7 Technical specifications
7.1 Measuring interface
The 855 Robotic Titrosampler has one galvanically isolated measuring inter-
face.
The measuring cycle is 100 ms for all measuring modes.
7.1.1 Potentiometry
One high-ohm measuring input (Ind.) for pH, redox or ISE electrodes and
one reference measuring input (Ref.) for a separate reference electrode.
Input resistance >1· 10 12 Ω
Offset current <1· 10 -12 A (under reference conditions)
Measuring mode
Measuring
range -20…+20 pH
Resolution 0.001 pH
0.1 mV
Measuring accu-
racy ±0.003 pH
±0.2 mV
(±1 digit, without sensor error, under reference conditions)
7.1.2 Polarizer
A measuring input (Pol.) for a polarizable electrode.
Measuring mode
Ipol Determination with adjustable polarization current.
Polarization cur-
rent –125.0…+125.0 µA (in increments of 2.5 µA)
–125…–121 µA / +121…+125 µA: non-guaranteed values, dependent
on reference voltage +2.5 V
Measuring
range -1200…+1200 mV
Resolution 0.1 mV
Measuring
accuracy ±0.2 mV
(±1 digit, without sensor error, under reference conditions)
Measuring mode
Upol Determination with adjustable polarization voltage
Polarization
voltage -1250…+1250 mV (in increments of 25 mV)